1. Field of the Invention
The present invention relates to a large EL panel formed by a plurality of EL display devices, such as organic EL panels, which are arranged in a matrix pattern, and also relates to a manufacturing method for the large EL panel.
2. Description of the Related Art
Small EL flat panels (EL display devices) driven by polysilicon TFTs are usually laminated on a hard and transparent substrate by an adhesive, etc., in order to maintain the flatness thereof. Each of the TFTs control the driving of one of multiple pixels in the EL display devices, so that plane images are displayed.
The EL display devices as described above are typically two to six inches in length measured in a diagonal direction, and provide excellent functions as small image displays.
Conventionally, in theaters and stadiums, large screens, which are capable of displaying clear images, are commonly used in place of electrical scoreboards. In such large screens, a plurality of light sources, such as the above-described EL display devices, light bulbs are arranged in a matrix pattern. Each of the light sources functions as a pixel for forming an image.
In such theaters and stadiums, there is a sufficient distance between the screen and the audience; therefore, the EL display devices having a diagonal length of, for example, several inches should not be a problem.
Recently, on the other hand, instead of CRTs, liquid crystal display panels have been commonly used as displays for televisions and personal computers. In addition, there has been a demand to increase the sizes of the liquid crystal display panels.
In a liquid crystal display, an additional light source is required as a backlight. Thus, to increase the size of the liquid crystal display, the size of the backlight must also be increased. The present situation, however, is such that when a large (50 to 100 inches in diagonal length) and thin display is required, an amount of heat, which increases along with the size of the backlight, will be too large. In addition, the thickness of the display cannot be made thin enough to satisfy the requirement.
Accordingly, the use of the EL display devices driven by TFTs, which will be referred to as TFT-EL display devices in the following disclosure, has been considered. In the TFT-EL display devices, the backlights are not required. In addition, due to the use of the TFTs, the number of pixels may be increased, and response rate becomes higher, so that high-resolution images may be displayed.
Large TFT-EL display devices, however, have not been realized. Accordingly, to form a large display panel which is 20 to 100 inches in diagonal length, small TFT-EL display devices, which are several inches in diagonal length, must be arranged in a matrix pattern.
In addition, a TFT array includes not only a pixel section but also a circuit (driver) section for individually controlling the light emission at the pixels. The circuit section is disposed at a region outside of an image forming area, and prevents the adjacent EL display devices from being arranged in close proximity to each other.